S5411 Metastatic Small Cell Lung Carcinoma Presenting With Hepatic Nodularity and Transaminitis Mimicking Budd-Chiari Syndrome

Introduction: Small cell lung carcinoma (SCLC) is a rapidly progressive neuroendocrine malignancy that frequently metastasizes to the liver. Hepatic involvement may present with hepatomegaly, jaundice, transaminitis, and portal hypertension. Infiltrative liver metastases can radiographically mimic vascular disorders such as Budd-Chiari syndrome, leading to diagnostic uncertainty. This case highlights the importance of integrating imaging, tumor markers, and liver biopsy for definitive diagnosis. Case Description/Methods: A 61-year-old woman with coronary artery disease, hypertension, diabetes, and a heavy smoking history presented with abdominal pain, jaundice, nausea, and unintentional weight loss. Laboratory findings revealed aspartate aminotransferase 775 U/L, alanine aminotransferase 121 U/L, alkaline phosphatase 565 U/L, and total bilirubin 7.8 mg/dL. Abdominal computed tomography (CT) demonstrated hepatomegaly with nodularity, colonic wall thickening, and a right middle lobe lung opacity. magnetic resonance imaging (MRI) showed segmental hepatic lesions with perfusion abnormalities and suggested hepatic outflow obstruction. Doppler ultrasound confirmed patent hepatic and portal veins, ruling out Budd-Chiari syndrome. Further evaluation of Chest CT revealed right hilar lymphadenopathy, pulmonary nodules, and middle lobe opacities suspicious for neoplasm. MRI Pelvis revealed a complex ovarian mass and osseous lesions concerning for metastatic disease. Tumor markers were elevated: CA 125, CA 19-9, and carcinoembryonic antigen, with normal alpha-fetoprotein. Heparin initiated for presumed Budd-Chiari was discontinued. A trans jugular liver biopsy revealed a hepatic venous pressure gradient of 12 mmHg and histopathology consistent with metastatic small cell carcinoma. Immunohistochemistry was positive for pan-cytokeratin, CK7, CD56, synaptophysin, chromogranin, and TTF-1, confirming pulmonary origin. The Ki-67 proliferation index was 100%. Discussion: This case demonstrates an unusual hepatic presentation of metastatic SCLC, initially raising concern for Budd-Chiari syndrome. Hepatic metastases may mimic hepatic venous outflow obstruction radiographically due to sinusoidal compression. However, Doppler ultrasound remains a key tool in excluding vascular obstruction. The definitive diagnosis relied on liver biopsy and immunohistochemical staining, with TTF-1 and neuroendocrine markers supporting lung origin. Prompt recognition is critical, as SCLC has a poor prognosis and requires early oncologic intervention.